Ignition switch now!
 

My car has sat with no battery over winter and I am now putting a new one in. This is obviously going to have wiped the data from the car but I have some questions. Is the alarm still going to recognise the key when I go to use the car? Also should I put the ignition to the first postition when I connect the battery?

My friend did the same thing several years ago on his '02. If you reinstall the battery, you will be fine; no need to position the ignition key. Yes, the cumulative data in the ECU will be gone and will take at least a week of various driving conditions to rebuild. IN my friend's case, the car would not pass emissions since the ECU status did not contain enough driving history to clear ready codes. As far as the immobilizer, that is all contained within flash memory, so it will not be an issue.

Brilliant. Thanks a lot. One further point - i'm not sure if my ignition switch is busted as it is difficult to get it to "0". If I plug the battery in and the ignition is trying to get to "1" but i've taken the key out so it is stuck at "0" do you think this is more likely to bust it and therefore I should insert the key to position one to be on the safe side? Ie will it cause any problems if I do put it to position one when inserting the new battery?
Thanks

Key position shouldn't matter. When I was replacing my ignition switch I turned it through all the positions without a key in the ignition and set off about every alarm on the car. I was making sure the new switch worked correctly. After I put everything back together the car started fine.

The key has 2 functions. It has a transponder that tells the alarm control unit (ACU) that you have a legitimate key and aren't hot wiring the car. If your key fob doesn't have the transponder pill in it, or the ACU doesn't have the correct transponder number stored then your alarm will go off and the car won't start. The other function is to act as a remote. This won't work initially, as after 5 days the remote function is disabled to save battery. The remote function is restored after the door is unlocked manually or the car is started. It's one of the two and I can't remember exactly which, but it's in the manual. My ACU "lost" the code for the remote. This required replacing the remote ($250 part+labor) because the code is attached to a paper slip when you get a new remote. The dealership went under and the paper slip went with it...lucky me.

Your ECU may or may not have forgotten the fuel map, but it'll learn that fast enough. Expect a little rough idle at first. I had my battery out for 6 months and when I got it going again I had the following issues. The spoiler was sticking. I got the warning light and had to retract the spoiler manually after the first trip on the highway. I also got a secondary air system failure code, and CEL, because one of the solenoid valves was sticking closed. After a few days, and running the spoiler in and out manually a few times, both issues cleared up.

Radio, you're going to need a new radio code to get the factory head unit working again. Try Loren at the Renntech forums. My ode from him didn't work though.
Here's the link for that:
http://www.renntech.org/forums/index.php?/topic/14539-lost-radio-code-post-your-request-here/
There's a sticky post there. I had to get one from a third party site and paid 12 pounds for it, but it worked.
http://www.radio-code.co.uk/porsche-radio-codes.html

So if i'm understanding right I can put the key in to the ignition at position one and connect the battery? Remember, i'm not certain that my ignition switch has gone - it certainly feels like it but it could be lack of power (I hope). Also, do you know if I will be able to drive it to Audi to pick up a new ignition switch if I do need one?

Doesn't matter what position the switch is in when you attach the battery. This is just a mechanical switch. I have an automatic so I'm having a hard time imagining what exactly you've done to the ignition switch. I assume you mean you've pulled the key when it was in the "run" position. IE where it would be when the car is running, instead of turning it back off. I'm not sure you should be able to do that, and it might be an indication that your switch is going bad. I'd have to play with it a bit to figure out what is wrong with the switch.

As far as the car alarm is concerned, the position doesn't matter, as long as the key is in the ignition. If you hook up the battery with the switch out of the off position, it's possible you'll get the alarm. If you do, you just need to put the key into the ignition to turn it off.

If the switch is really broke, you're not going anywhere. Put the key in, hook the battery up and see if it starts. You may need to take the key back to the off position before you try to start it. The part is pretty cheap online if you need to replace it. I think Pedro has a walk through for replacing the switch. I would recommend having very short small screw drivers!

I think the switch broke at position one. Therefore I had to force it to position zero in order to remove the key. I am hoping (a little naiively I think) that this was down to the dead battery and all will be well when I reconnect the new one.
I'll try it with the key in at position one and see what happens!

Now an ignition switch question
 

I changed the battery and started the car. All worked fine except for the ignition. It's still difficult to remove the key and I can't lock the car with the remote. Does this smell of an ignition switch or do you think it is something else as I was able to start the car?
Thanks

yep - sounds like classic ignition switch failure. Dash lights still on? Radio still paying? No loud 'clunk' when removing key?

Best to disconnect battery between uses until you get ignition switch fixed so as to not drain your new battery...

Part (from an Audi dealer) should only be ~ $35. Can be had online for $8.65 from www.************************************************************ so weigh your options b/w express shipping from them vs local pick up.

:)

EDIT - sorry, just saw you are in UK so above is reference to prices here in US

You should NOT have a key in the ignition when you install the battery!

Cheers!

The key not going through all the positions easily is probably the switch in the back, which as the guy above me pointed out is not expensive. Make sure you get the right part. Then it's just a matter of wedging yourself under the dash and swapping it out. The remote not working is probably something you'll have to take to a dealership. If replacing the switch doesn't fix the remote problem then it's probably the issue I described above which is only fixable at a shop/dealership that can do warranty work on Porsches. There are special codes, based on your vin number, that are required to reprogram the remotes, and I believe that Porsche will only hand those out to official Porsche shops.

The ignition barrel likely just needs a lube, if you look in the Bentley manual, it has a nice close up of how it comes apart. Mine started doing the same thing, took it apart sprayed it with break free, all is well.

Thanks all. Changed ignition switch and all fine. I must say it's very difficult to get to those screws on a LHD!
Thanks again, very much appreciated.